The present invention relates to a valve suitable for controlling teeming from a furnace taphole e.g. of an arc furnace.
When an arc furnace is tapped conventionally, molten metal and slag flow over the furnace pouring lip as the furnace is tilted. The metal and slag then run down a trough, where such is provided, and gather in a ladle. The presence of slag is a considerable inconvenience. Thus, it would be advantageous to be able to empty the furnace of its molten metal and to leave the slag behind.
By providing the furnace with a taphole located well below the top thereof, it is possible to pour off the molten metal alone when the furnace is tilted. Some form of stopper is needed to close the taphole until pouring is to take place. Better still would be a valve openable and closable at will, for this would facilitate the filling of several ladles from one furnace charge, and the furnace would only need tilting once, at the start of the emptying operation.
In principle a sliding gate valve might appear suitable for controlling flow out of the taphole. However, no known sliding gate valve is suitable. The known valve mechanism occupy considerable space to either side thereof i.e. along the direction of movement of the sliding valve plate. Adequate space is absent in the region of a furnace taphole, however, in part due to the presence of the pouring trough.